Thermodynamic activity(1) S.J.T.U. Phase Transformation and Applications Fugacity is defined for gases: dGi RTd(Infi) Thermodynamic activity of a component,i,is defined as: n0 The fugacity of the componentiin its standard state. The fugacity of a condensed phase is equal to the fugacity of the vapor phase in equilibrium with it. The fugacity of the vapor is equal to the pressure of the vapor,if the vapor in equilibrium with the condensed phase is ideal. SJTU Thermodynamics of Materials Spring2007©X.J.Jin Lecture 11 Solution IPhase Transformation and Applications S. J. T. U. SJTU Thermodynamics of Materials Spring 2007 © X. J. Jin Lecture 11 Solution I )(ln i i = fRTdGd D i i i f f α ≡ Thermodynamic activity (1) Fugacity is defined for gases: Thermodynamic activity of a component, i, is defined as: D i f The fugacity of the component i in its standard state. The fugacity of a condensed phase is equal to the fugacity of the vapor phase in equilibrium with it. The fugacity of the vapor is equal to the pressure of the vapor, if the vapor in equilibrium with the condensed phase is ideal